If you have your Google Cardboard VR viewer, you just need to download the app.

Recommended:
Close all running apps before launching the Safety in a Box app.

Note:
This app works on phones and tablets and optionally uses a Google Cardboard viewer, Gear VR, Google Daydream View, or similar VR viewing device, but does not require button input for navigation. For best performance, use smart phones from 2016 forward.